Systems for selectively feeding chunk polysilicon or granular polysilicon in a crystal growth chamber

1. A valve mechanism for controlling the flow of polysilicon from a granular tray of a polysilicon feed assembly to a growth chamber for growing a crystal ingot from a melt, the valve mechanism comprising: a seal that selectively obstructs an exit of the granular tray; a driver configured to raise and lower the seal between a sealed position obstructing the exit and an open position in which the seal does not obstruct the exit; and a linkage connecting the seal to the driver, wherein the seal is shaped to permit a gap between a portion of the exit of the granular tray such that granular polysilicon within the exit does not prevent a seal between the seal and the exit.

2. The valve mechanism as set forth in claim 1 wherein: the exit includes an opening; and the seal includes: a portion having a radius shaped to engage with the opening of the exit and having a same slope as the opening of the exit; and a second portion having a radius smaller than the opening of the exit and that is at least partially within the opening of the exit when the seal is in the sealed position, wherein the difference between the radius of the second portion and the radius of the opening of the exit defines the gap.

3. A polysilicon feed system comprising: a polysilicon feeder for supplying polysilicon to a growth chamber for growing a single crystal ingot from a melt; a magnetic pulse vibrator for vibrating the tray; a granular tray disposed above the vibrator, the granular tray having an exit; the valve mechanism as set forth in claim 1 , the seal of the valve mechanism selectively obstructing the exit of the granular tray and being shaped to permit a gap between a portion of the exit of the granular tray such that granular polysilicon within the exit does not prevent a seal between the seal and the exit.

4. The polysilicon feed system as set forth in claim 3 wherein the polysilicon feeder comprises support rails for receiving the granular tray.

5. The polysilicon feed system as set forth in claim 3 wherein the granular tray is an interchangeable granular tray.

6. The polysilicon feed system as set forth in claim 5 wherein the polysilicon feeder comprises support rails for receiving the interchangeable granular tray.

7. The polysilicon feed system as set forth in claim 6 wherein the granular tray comprises: an exterior portion that includes an exterior channel that removably receives the support rails of the polysilicon feeder; and an interior profile that receives granular polysilicon from a feed material reservoir of the polysilicon feeder.